Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V10_2/V10_200.TXT

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Subject: SPACE Digest V10 #200

SPACE Digest                                     Volume 10 : Issue 200

Today's Topics:
                Rocketry paper
              Re: Manned Jupiter Mission
            Re: More Info On NASP
            Fragile Space Shuttle
              Re: Manned Jupiter Mission
 Re: Manned Jupiter Mission (was Re: Condensed CANOPUS - August 1989)
     Magellan Status for 10/31/89 [Corrected] (Forwarded)
           Re:  Confederacy posting, copy received
           Galileo Status for 10/30/89 (Forwarded)
 Re: Manned Jupiter Mission (was Re: Condensed CANOPUS - August 1989)
----------------------------------------------------------------------

Date: 1 Nov 89 17:40:49 GMT
From: gem.mps.ohio-state.edu!uwm.edu!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!m.cs.uiuc.edu!bucc2![e-mail]
Subject: Rocketry paper


I am doing a paper on the pre-Sputnik, post-1900 days of rocketry, &
I'd like to know if there are any books on that subject. Please give
any information to:

uiucdcs\
    noao>bradley!bucc2!moonman
   cepu/

Internet: bradley!bucc2![e-mail]
Arpa: cepu!bradley!bucc2![e-mail]

Thanks a lot in advance.

------------------------------

Date: 1 Nov 89 17:50:24 GMT
From: frooz![e-mail]  (Steve Willner)
Subject: Re: Manned Jupiter Mission

From article <[e-mail]>, by
[e-mail] (Henry Spencer):
[On stopping cosmic rays with magnetic fields]
> One problem is that it's the very highest energies
> that are the big worry; stopping the low 99% is not good enough.

This must be a question of generation of secondary particles, not
biological effectiveness of the primaries.  (Biological effectiveness
diminishes with increased energy.)  Magnetic shielding generates many
fewer secondaries than shielding with matter, since interaction with
matter is what generates the secondaries.

A quick calculation for the magnetic field strength necessary gives
B=mvc/r, where B is magnetic induction ("magnetic field") in gauss, m
is particle mass in grams, c is speed of light in cm/s, and r is
desired radius of curvature in cm.  (This is non-relativistic; for
relativistic, just put gamma in front and note that v is nearly equal
to c.  I haven't looked this up, but I'm pretty sure it's right.)
Putting in numbers for 100 MeV protons, I get only 10^-5 gauss to give
a 1 meter radius of curvature, so the field strengths needed don't seem
all that high, even putting in a distance^-3 dependence for dipole-like
fields.  (The implication is that magnet sizes must be of order one
meter.)  The pattern of fields to use is another question; I doubt a
simple dipole would do much good.

Does anybody have a good idea just what energies have to be stopped,
bearing in mind that particles with higher energies will penetrate
rather freely and will not encounter a massive shield?
-------------------------------------------------------------------------
Steve Willner            Phone [phone]         Bitnet:   willner@cfa
60 Garden St.            FTS:      830-7123           UUCP:   willner@cfa
Cambridge, MA 02138 USA                 Internet: [e-mail]

------------------------------

Date: Mon, 30 Oct 89 06:54:13 PST
From: mordor!lll-tis!oodis01!riacs!rutgers!pnet01.cts.com![e-mail] (Jim Bowery)
To: ucsd!nosc!crash![e-mail]
Subject: Re: More Info On NASP


Larry Smith writes:

>A big problem above Mach 7-8 now is what inefficiency percentage
>do you assign to your scramjet engine model components, due to the
>fact that above Mach 7-8, we have no real data to validate the codes?

A whole bunch of us have been asking this question of NASP ever
since its inception.  Maybe the program is in so much trouble they
finally decided to get real and try to validate all these marvelous
computer models that are supposed to allow us to go from concept to
flying prototype (X30) with virtually no emperical intermediates.

Unfortunately, such validation will require emperical activities.  *sigh*
Ya just can't win em all.

>Now this is NOT an indictment of scramjets, but it shows
>the current REAL NEED to build HARDWARE to work some of these things
>out. This is really the goal of X-30/NASP. NOT to build a Orient
>Express, or a new SR-71, or even a payload orbiter. But, to
>develop the required technologies to potentially build NASP Derived
>Vehicles (NASPDV or NDV), and NASP Technology Derived Vehicles (which may
>not be airplanes at all. ex: high L/D orbital transfer vehicles that
>can do orbital plane changes with air breathing engines via the upper
>atmosphere, new high Isp air breathing rockets, new cargo shuttles
>without tiled skins).

Right, Larry.  They pull out the old viewgraphs that were used to
sell the Shuttle as an operational vehicle capable of bringing the
cost per pound to LEO down by a factor of 100 to 1000 after a
development project of only $5 billion, and you think the real goal
of NASP is to BUILD anything?

The REAL GOAL of NASP is, as many of us who haven't forgotten history
have been trying to tell the space nerds all along, to start yet
another Big Development Project justified by chanting "WE HAVE THE
TECHNOLOGY" before the appropriate subcommittees.  After we have
committed all our resources to the DEVELOPMENT of ONE idea, we
decide to call it a "research" project, (sort of like the Shuttle not
being expected to really be economical because it is a "research
vehicle") other ideas can then try to find funding in an environment
of vested interests, bureaucracy and political sleaze.

What a way to run a science budget.
---------------------------------------------------------------------------
Jim Bowery      PHONE: [phone]     BE A SPACE ACTIVIST
PO Box 1981            GET OFF THE NET AND SET UP AN APPOINTMENT WITH YOUR
La Jolla, CA 92038                         CONGRESSMAN!
---------------------------------------------------------------------------
UUCP: {cbosgd, hplabs!hp-sdd, sdcsvax, nosc}!crash!pnet01!jim
ARPA: crash!pnet01![e-mail]
INET: [e-mail]

------------------------------

Date: Wed, 1 Nov 89 20:33 EDT
From: Nutsy Fagen <[e-mail]>
Subject: Fragile Space Shuttle

        Okay, another question for you.  Every time the shuttle goes up or
comes down, I read about how just about every system is checked, removed,
replaced, etc.  I can understand a thorough checkout, and the fact that
space travel is, to say the least, a risky business, but how much of what
NASA does for turnaround would be considered unneccesary in 10-15 years
(Provided the same shuttle design is still running).
        Few of us have a problem with a commercial plane ride in bad weather,
yet we read that they can't even roll the shuttle to the pad because of rain!
This also reminds me of just about every nut and fastener being traceable to
who installed it, when, where it came from, etc.
        As I said before, I agree that such stringent measures are required
at our current level of knowledge with space travel.  What I am really
wondering is how low until things start to 'ease off'.  What will be the first
requirements that get dropped?  And, when will the astronauts get to stop
wearing those uncomfortable orange suits?

Mike Bunell
MJB8949 @ RITVAX
I R a student
No boss
No disclaimer
no job

------------------------------

Date: 2 Nov 89 01:45:24 GMT
From: calvin![e-mail]  (John Sahr)
Subject: Re: Manned Jupiter Mission

In article <[e-mail]> [e-mail] (Steve Willner) writes:
>From article <[e-mail]>, by
>[e-mail] (Henry Spencer):
>[On stopping cosmic rays with magnetic fields]
>> One problem is that it's the very highest energies
>> that are the big worry; stopping the low 99% is not good enough.
>
>This must be a question of generation of secondary particles, not
>biological effectiveness of the primaries.  (Biological effectiveness
>diminishes with increased energy.)  Magnetic shielding generates many
>fewer secondaries than shielding with matter, since interaction with
>matter is what generates the secondaries.
>
>
>A quick calculation for the magnetic field strength necessary gives
>B=mvc/r, where B is magnetic induction ("magnetic field") in gauss, m
 ^^^^^^^

So close, and yet so far.  This equation would be correct it the proton
charge was included:

B = mvc/(er)   where e = 4.8x10^-10 cgs

>is particle mass in grams, c is speed of light in cm/s, and r is
>desired radius of curvature in cm.  (This is non-relativistic; for
>relativistic, just put gamma in front and note that v is nearly equal
>to c.  I haven't looked this up, but I'm pretty sure it's right.)
>Putting in numbers for 100 MeV protons, I get only 10^-5 gauss to give
[]                                                  ^^^^^
In the earth's lower ionosphere, where B is approximately 0.5 gauss, the Larmor
radius for NO+ is about 200 cm.  The magnetic field embedded in the solar
wind has a typical size of a few times 10^-5 gauss, so no shielding would
be necessary in the solar system if that was enough B.

Plugging in that unfortunate factor of e changes that 10^-5 "gauss"
to 2x10^+4 gauss, or 2 Tesla (for the MKSeoisie).  Now, 2 T fields are
possible today, but 2 T is big.  Things that make 2 T fields in people sized
volumes are large and heavy.  You might be better off turning the darn
magnet off and re-casting it into a shield.  Save on the electric bill, too.

my own opinions, of course.--
John Sahr,                   | Electrical Engineering - Space Plasma Physics
[e-mail] | Cornell University,         Ithaca, NY  14853

------------------------------

Date: 31 Oct 89 17:32:38 GMT
From: datapg!com50!questar![e-mail]  (Al Viall)
Subject: Re: Manned Jupiter Mission (was Re: Condensed CANOPUS - August 1989)

In article <[e-mail]>, [e-mail] (Henry Spencer) writes:
> In article <[e-mail]> [e-mail] (Mark Gellis) writes:
> >I've heard talk of using magnetic fields to deflect cosmic rays, particles,
> >etc.  This would supposedly lower the mass of the hull necessary to protect
> >the crew of a spacecraft from radiation.  Is this true?  Workable?  What is
> >involved in setting up such a "radiation shield"?
>
> It's theoretically possible but complicated.  The designs I'm aware of
> for things like space colonies all use brute-force mass rather than
> magnetic shielding.  One problem is that it's the very highest energies
> that are the big worry; stopping the low 99% is not good enough.
>
Much of the opinion of the late sixties and early seventies was that craft
built for the long haul in the future would be better built out of the shell
of a small asteroid.
There are some interesting reports on using planetary objects as spacecraft.

Although such a thing would take a herculean effort, this option would leave
much for the shielding of cosmic rays. The mas would be there, the work would
be hollowing it out, the problem would be propulsion.


--
| INTERNET: [e-mail]      |    NEW PRODUCT ON THE MARKET     |
|     UUCP: ..!amdahl!tcnet!questar!al     |        "Flame in a Can"          |
|  FIDONET: 1/282:2,3 (Al Viall)           | Just tear off the protective     |
| "MMMMMMM. And so good for you!"          | seal, point and shoot. Great fun!|

------------------------------

Date: 2 Nov 89 01:15:34 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Magellan Status for 10/31/89 [Corrected] (Forwarded)


                     MAGELLAN WEEKLY STATUS
                          Oct. 31, 1989

CORRECTED: Pgh 4, It is the first software patch, not the first
star scanner, as indicated.


     This is the weekly Magellan status report. Magellan on
Tuesday, Oct. 31, was 80,889,686 miles from Earth. Having passed
through perihelion on Oct. 7, the spacecraft is slowing as it
begins its return to the orbit of earth and is now traveling at a
speed of 83,205 miles per hour relative to the sun.

     With the exception of several failed star calibrations,
Magellan continues to operate nominally during the second third
of its cruise.

     None of the seven scheduled star calibrations performed last
week provided a complete autonomous attitude update. On Oct. 24,
although the star Beta Gruis was rejected due to the magnitude
check, all four star crossings were found to be valid. The
attitude control system analysts were then able to use the data
to generate an attitude knowledge correction. It was tested and
uplinked on Oct. 27.

     During the weekend, the command file to change star pairs
was tested and is expected to be uplinked Thursday, Nov. 2.
Additionally, the first software patch to help alleviate the
star calibration problem was uplinked to the spacecraft today,
Oct. 31.

     Preparations for Cruise load 14 and 15 are proceeding on
schedule. The start of Cruise 14 stored sequence is scheduled for
Nov. 6 and Cruise 15 on Nov. 28.



     SPACECRAFT
     Distance from Earth (mi)             80,889,686

     Velocity Geocentric                  66,573 mph
              Heliocentric                883,205 mph

     One-way light time (Oct. 30)         7 mins, 10 secs

------------------------------

Date:     Wed, 1 Nov 89 14:53:19 CST
From: Will Martin <[e-mail]>
Subject:  Re:  Confederacy posting, copy received

Thanks to Frank Paterra, I now have a copy of the Confederacy posting, and
I've forwarded it to the SPACE moderator so it can get into the Digest
without bouncing back out on USENET again.

Regards, Will

------------------------------

Date: 1 Nov 89 20:53:54 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Galileo Status for 10/30/89 (Forwarded)


                      GALILEO WEEKLY STATUS
                        October 30, 1989


          This is a weekly Galileo status report.  Today,
October 30, 1989, the spacecraft is about 2.5 million miles from
Earth, and has gone 16.7 million along its 2.4-billion-mile
spiral course to Jupiter.  Its velocity around the Sun is almost
60,000 mph.  All subsystems are working well.

          Since launch, operators have sent hundreds of real-
time commands to the Galileo spacecraft. The S-band transmitter
has been switched to 30 watts, and the propulsion system has been
exercised twice in maintenance maneuvers (primarily to move
oxidizer and fuel along in the plumbing.)  The telemetry rate is
7.68 kilobits per second.

          As of this morning, the spacecraft is spinning at 2.9
rpm around an axis within 1 degree of the Sun line.  As Galileo
progresses around towards Venus, the Sun angle changes; this is
held to less than 14 degrees, by commanded or automatic
maneuvers, to assure a shaded spacecraft.

          The atmospheric entry probe was checked out last
Thursday, October 26, and its condition is satisfactory.  The
imaging system and the near-infrared mapping spectrometer
were checked out Friday, with good results.  Preparatory
activities for various other science instruments are being
done, but the only instruments actually turned on and taking
data are the magnetometer and the HIC.

          The heavy ion counter, an engineering instrument
modified from parts of a Voyager cosmic-ray sensor, was
turned on ten days ago and detected the latter part of the
solar flare of October 19.  Heavy ions of energies up to 130
MEV (million electron volts) have been detected, but the
spacecraft has experienced no single-event upsets (i.e., no
ill effects.)

          Today the star sensor on the spinning section is to
be checked out, in preparation for Wednesday's start of dual-
spin operations.  The lower section of the Galileo spacecraft
will be spun in reverse, with electric motors, stopping the
rotation and despinning the science scan platform.

          The first trajectory-correction maneuver, TCM-1, is
scheduled, in three instalments, for November 9, 10 and 11.

------------------------------

Date: 1 Nov 89 22:12:07 GMT
From: agate!sandstorm.Berkeley.EDU![e-mail]  (George William Herbert)
Subject: Re: Manned Jupiter Mission (was Re: Condensed CANOPUS - August 1989)

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (John E Van Deusen III) writes:
>>> Manned Jupiter missions could *really* *really* use better propulsion...
>>
>>After it comes around for the second time, intercept it with a high-
>>performance, crew-carrying, orbital shuttle and make the comparatively
>>quick journey in comfort and safety.
>
>"Comparatively quick"?  Can you elaborate on this?  Even after Galileo's
>fiddling around in the inner solar system, its transit time to Jupiter
>is still measured in years.  Human exploration of the outer solar system
>is difficult, verging on impractical, unless propulsion is good enough to
>let you forget about economy orbits and use fast ones instead.

A friend did a design for a contest for a manned jupiter mission.  His
solution was using NERVA rockets.  Nothing else works, realistically.


****************************************
George William Herbert  UCB Naval Architecture Dpt. (my god, even on schedule!)
[e-mail] [[e-mail], but i don't check mail often]
----------------------------------------

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End of SPACE Digest V10 #200
*******************